71M6543GHT-IGTSLASHF datasheet(20/75 Pages) MAXIM

20 / 75 page

Maxim Integrated │ 20

71M6543FT/71M6543HT/

71M6543GT/71M6543GHT

Energy Meter ICs

www.maximintegrated.com

Hardware Description

The 71M6543FT/HT/GT/GHT single-chip energy meter

ICs integrate all primary functional blocks required to

implement a solid-state residential electricity meter.

Included on the chip are the following:

• An analog front-end (AFE) featuring a 22-bit second-

order sigma-delta ADC

• An independent 32-bit digital computation engine (CE)

to implement DSP functions

• An 8051-compatible microprocessor (MPU) which

executes one instruction per clock cycle (80515)

• A precision voltage reference (VREF)

• Atemperature sensor for digital temperature compensation:

•

Metrology digital temperature compensation (MPU)

•

Automatic RTC digital temperature compensation

operational in all power states

• LCD drivers

• RAM and flash memory

• A real-time clock (RTC)

• A variety of I/O pins

• A power-failure interrupt

• A zero-crossing interrupt

• Selectable current sensor interfaces for locally-connect-

ed sensors as well as isolated sensors (i.e., using the

71M6x03 companion IC with a shunt resistor sensor)

• Resistive shunt and current transformers are supported

Resistive shunts and current transformer (CT) current

sensors are supported. Resistive shunt current sensors

may be connected directly to the 71M654xT device

or isolated using a companion 71M6x03 isolator IC in

order to implement a variety of metering configurations.

An inexpensive, small pulse transformer is used to

isolate the 71M6x03 isolated sensor from the 71M654xT.

The 71M654xT performs digital communications

bidirectionally with the 71M6x03 and also provides power

to the 71M6x03 through the isolating pulse transformer.

Isolated (remote) shunt current sensors are connected

to the differential input of the 71M6x03. Included on the

71M6x03 companion isolator chip are:

• Digital isolation communications interface

• An analog front-end (AFE)

• A precision voltage reference (VREF)

• A temperature sensor (for digital temperature compen-

sation)

• A fully differential shunt resistor sensor input

• A preamplifier to optimize shunt current sensor perfor-

mance

• Isolated power circuitry obtains dc power from pulses

sent by the 71M654xT

In a typical application, the 32-bit compute engine (CE)

of the 71M654xT sequentially processes the samples

from the voltage inputs on analog input pins and from

the external 71M6x03 isolated sensors and performs

calculations to measure active energy (Wh) and reactive

energy (VARh), as well as A2h, and V2hforfour-quadrant

metering. These measurements are then accessed by the

MPU, processed further and output using the peripheral

devices available to the MPU.

In addition to advanced measurement functions, the clock

function allows the 71M6543FT/HT/GT/GHT to record

time-of-use (TOU) metering information for multi-rate

applications and to time-stamp tamper or other events.

Measurements can be displayed on 3.3V LCDs commonly

used in low-temperature environments. Flexible mapping

of LCD display segments facilitate integration of existing

custom LCDs. Design trade-off between the number of

LCD segments and DIO pins can be implemented in

softwaretoaccommodatevariousrequirements.

In addition to the temperature-trimmed ultra-precision

voltage reference, the on-chip digital temperature

compensation mechanism includes a temperature sensor

and associated controls for correction of unwanted

temperature effects on measurement and RTC accuracy,

e.g.,tomeettherequirementsofANSIandIECstandards.

Temperature-dependent external components such as

crystal oscillator, resistive shunts, current transformers

(CTs) and their corresponding signal conditioning circuits

can be characterized and their correction factors can be

programmed to produce electricity meters with exceptional

accuracy over the industrial temperature range.

One of the two internal UARTs is adapted to support an

Infrared LED with internal drive and sense configuration

and can also function as a standard UART. The optical

output can be modulated at 38kHz. This flexibility makes

it possible to implement AMR meters with an IR interface.

A block diagram of the IC is shown in Figure 1.

71M6543GHT-IGT/F 数据表(PDF) 20 Page - Maxim Integrated Products

71M6543GHT-IGT/F 数据表(HTML) 20 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

数据表下载